<template>
    <div class="play">
        <!-- 模糊背景(靠样式设置), 固定定位 -->
        <div
                class="song-bg"
                :style="`background-image: url(${
        songInfo && songInfo.al && songInfo.al.picUrl
      }?imageView&thumbnail=360y360&quality=75&tostatic=0);`"
        ></div>
        <!-- 播放页头部导航 -->
        <div class="header">
            <van-icon
                    name="arrow-left"
                    size="20"
                    class="left-incon"
                    @click="$router.back()"
            />
        </div>
        <!-- 留声机 - 容器 -->
        <div class="song-wrapper">
            <!-- 留声机本身(靠css动画做旋转) -->
            <div
                    class="song-turn ani"
                    :style="`animation-play-state:${playState ? 'running' : 'paused'}`"
            >
                <div class="song-img">
                    <!-- &&写法是为了防止报错, 有字段再继续往下访问属性 -->
                    <img
                            style="width: 100%"
                            :src="`${songInfo && songInfo.al && songInfo.al.picUrl}?imageView&thumbnail=360y360&quality=75&tostatic=0`"
                            alt=""
                    />
                </div>
            </div>
            <!-- 播放按钮 -->
            <div class="start-box" @click="audioStart">
                <span class="song-start" v-show="!playState"></span>
            </div>
            <!-- 播放歌词容器 -->
            <div class="song-msg">
                <!-- 歌曲名 -->
                <h2 class="m-song-h2">
          <span class="m-song-sname"
          >{{ songInfo.name }}-{{
              songInfo && songInfo.ar && songInfo.ar[0].name
            }}</span
          >
                </h2>
                <!-- 歌词部分-随着时间切换展示一句歌词 -->
                <div class="lrcContent">
                    <p class="lrc">{{ curLyric }}</p>
                </div>
            </div>
            <!-- 留声机 - 唱臂 -->
            <div class="needle" :style="`transform: rotate(${needleDeg});`"></div>
        </div>
        <!-- 播放音乐真正的标签
          看接口文档: 音乐地址需要带id去获取(但是有的歌曲可能404)
          https://binaryify.github.io/NeteaseCloudMusicApi/#/?id=%e8%8e%b7%e5%8f%96%e9%9f%b3%e4%b9%90-url
         -->
        <audio
                ref="audio"
                preload="true"
                :src="`https://music.163.com/song/media/outer/url?id=${id}.mp3`"
        ></audio>
    </div>
</template>

<script>
    // 获取歌曲详情和 歌曲的歌词接口
    import {getLyricByIdAPI, getSongByIdAPI} from '@/api'
    import {Icon} from 'vant'

    export default {
        components: {
            [Icon.name]: Icon,
        },
        name: 'play',
        data() {
            return {
                playState: false, // 音乐播放状态(true暂停, false播放)
                id: this.$route.query.id, // 上一页传过来的音乐id
                songInfo: {}, // 歌曲信息
                lyric: {}, // 歌词枚举对象(需要在js拿到歌词写代码处理后, 按照格式保存到这个对象)
                curLyric: '', // 当前显示哪句歌词
                lastLy: '' // 记录当前播放歌词
            }
        },
        computed: {
            needleDeg() { // 留声机-唱臂的位置属性
                return this.playState ? '-7deg' : '-38deg'
            }
        },
        methods: {
            async getSong() { // 获取歌曲详情, 和歌词方法
                const res = await getSongByIdAPI(this.id);
                this.songInfo = res.data.songs[0];
                // 获取-并调用_formatLyr方法, 处理歌词
                const lyrContent = await getLyricByIdAPI(this.id);
                const lyricStr = lyrContent.data.lrc.lyric;
                this.lyric = this._formatLyr(lyricStr);
                // 初始化完毕先显示零秒歌词
                this.curLyric = this.lyric[0]
            },
            _formatLyr(lyricStr) {
                // 可以看network观察歌词数据是一个大字符串, 进行拆分.
                let reg = /\[.+?\]/g; //
                let timeArr = lyricStr.match(reg); // 匹配所有[]字符串以及里面的一切内容, 返回数组
                console.log(timeArr); // ["[00:00.000]", "[00:01.000]", ......]
                let contentArr = lyricStr.split(/\[.+?\]/).slice(1); // 按照[]拆分歌词字符串, 返回一个数组(下标为0位置元素不要,后面的留下所以截取)
                console.log(contentArr);
                let lyricObj = {}; // 保存歌词的对象, key是秒, value是显示的歌词
                timeArr.forEach((item, index) => {
                    // 拆分[00:00.000]这个格式字符串, 把分钟数字取出, 转换成秒
                    let ms = item.split(':')[0].split('')[2] * 60;
                    // 拆分[00:00.000]这个格式字符串, 把十位的秒拿出来, 如果是0, 去拿下一位数字, 否则直接用2位的值
                    let ss = item.split(':')[1].split('.')[0].split('')[0] === '0' ? item.split(':')[1].split('.')[0].split('')[1] : item.split(':')[1].split('.')[0];
                    // 秒数作为key, 对应歌词作为value
                    lyricObj[ms + Number(ss)] = contentArr[index]
                });
                // 返回得到的歌词对象(可以打印看看)
                console.log(lyricObj);
                return lyricObj
            },
            audioStart() { // 播放按钮 - 点击事件
                if (!this.playState) { // 如果状态为false
                    this.$refs.audio.play() // 调用audio标签的内置方法play可以继续播放声音
                } else {
                    this.$refs.audio.pause() // 暂停audio的播放
                }
                this.playState = !this.playState // 点击设置对立状态
            },
            showLyric() {
                // 监听播放audio进度, 切换歌词显示
                this.$refs.audio.addEventListener('timeupdate', () => {
                    let curTime = Math.floor(this.$refs.audio.currentTime);
                    // 避免空白出现
                    if (this.lyric[curTime]) {
                        this.curLyric = this.lyric[curTime];
                        this.lastLy = this.curLyric
                    } else {
                        this.curLyric = this.lastLy
                    }
                })
            }
        },
        mounted() {
            this.getSong();
            this.showLyric();
            console.log(this.$route.query.id);
        }
    }
</script>

<style scoped>
    .header {
        height: 50px;
    }

    .play {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: 1000;
    }

    .song-bg {
        background-color: #161824;
        background-position: 50%;
        background-repeat: no-repeat;
        background-size: auto 100%;
        transform: scale(1.5);
        transform-origin: center;
        position: fixed;
        left: 0;
        right: 0;
        top: 0;
        height: 100%;
        overflow: hidden;
        z-index: 1;
        opacity: 1;
        filter: blur(25px); /*模糊背景 */
    }

    .song-bg::before { /*纯白色的图片做背景, 歌词白色看不到了, 在背景前加入一个黑色半透明蒙层解决 */
        content: " ";
        background: rgba(0, 0, 0, 0.5);
        position: absolute;
        left: 0;
        top: 0;
        right: 0;
        bottom: 0;
    }

    .song-wrapper {
        position: fixed;
        width: 247px;
        height: 247px;
        left: 50%;
        top: 50px;
        transform: translateX(-50%);
        z-index: 10001;
    }

    .song-turn {
        width: 100%;
        height: 100%;
        background: url("./img/bg.png") no-repeat;
        background-size: 100%;
    }

    .start-box {
        position: absolute;
        width: 156px;
        height: 156px;
        position: absolute;
        left: 50%;
        top: 50%;
        transform: translate(-50%, -50%);
        display: flex;
        justify-content: center;
        align-items: center;
    }

    .song-start {
        width: 56px;
        height: 56px;
        background: url("./img/start.png");
        background-size: 100%;
    }

    .needle {
        position: absolute;
        transform-origin: left top;
        background: url("./img/needle-ab.png") no-repeat;
        background-size: contain;
        width: 73px;
        height: 118px;
        top: -40px;
        left: 112px;
        transition: all 0.6s;
    }

    .song-img {
        width: 154px;
        height: 154px;
        position: absolute;
        left: 50%;
        top: 50%;
        overflow: hidden;
        border-radius: 50%;
        transform: translate(-50%, -50%);
    }

    .m-song-h2 {
        margin-top: 20px;
        text-align: center;
        font-size: 18px;
        color: #fefefe;
        overflow: hidden;
        white-space: nowrap;
        text-overflow: ellipsis;
    }

    .lrcContent {
        margin-top: 50px;
    }

    .lrc {
        font-size: 14px;
        color: #fff;
        text-align: center;
    }

    .left-incon {
        position: absolute;
        top: 10px;
        left: 10px;
        font-size: 24px;
        z-index: 10001;
        color: #fff;
    }

    .ani {
        animation: turn 5s linear infinite;
    }

    @keyframes turn {
        0% {
            -webkit-transform: rotate(0deg);
        }
        100% {
            -webkit-transform: rotate(360deg);
        }
    }
</style>